Per-6-bromo-per-2,3-dimethyl-β-cyclodextrin

Amino Acid Derivatives of β-Cyclodextrin

“…Even at this stage, the solubility of 10 in low boiling organic solvents was noted to be much enhanced compared with that of the unmethylated analog, per-6-bromo-β-cyclodextrin, 17 which could be prepared by a procedure analogous to that employed in the synthesis of per-6-iodoβ-cyclodextrin (2). Single crystals of the per-6-bromoper-2,3-O-dimethyl-β-cyclodextrin (10), which proved to be of suitable quality for X-ray crystallographic analysis, 28 were grown by slow evaporation from an Me 2 O solution. The X-ray crystal structure reveals (Figure 1) that the conformation of the molecule departs significantly from C 7 symmetry.…”

X-ray crystallography and solution NMR spectroscopy characterization of heptakis(2,3-di-O-acetyl-6-bromo-6-deoxy)cyclomaltoheptaose

“…The solvent molecules in the cavity of 2 may help it not to collapse. The fact that the solvent has a stabilizing effect is also observed in the structure of heptakis(2,3-di-O-methyl-6-bromo-deoxy)-b-CD, 5 where entrapped acetone stabilizes the cavity. Therefore, it is apparent that the persubstituted cyclodextrin systems possess high versatility in the way they stabilize themselves and the existence of a guest (solvent) in the cavity increases this versatility and contributes to stabilization.…”

“…Perhalogenation of the primary hydroxyl groups 2;3 of b-cyclodextrin provides intermediates, such as heptakis(6-bromo-6-deoxy)cyclomaltoheptaose (1), useful for further chemical modifications, 4 which however, are soluble only in high boiling organic solvents (DMF, Me 2 SO). Therefore, the analogues heptakis(2,3-di-Omethyl-6-bromo-6-deoxy)- 5 and heptakis(2,3-di-O-acetyl-6-bromo-6-deoxy)- (2) 6 and heptakis(2,3-di-O-acetyl-6-iodo-6-deoxy)cyclomaltoheptaose 7 have been synthesized, which are soluble in common organic solvents.…”

Efficient Monomodification of the Secondary Hydroxy Groups of β-Cyclodextrin

“…Thus, we conclude that the structure of 2 is correctly assigned as being the result of highly selective silylation at one of the seven possible C-2 hydroxy groups. The structure of compound 5 was further confirmed by its conversion to compound 7 (FAB(M + Na + ) = 1700) . Compounds 5 and 6 can be readily formed from 2 , providing a synthetic pathway for selectively generating a β -cyclodextrin with only one free secondary hydroxyl group, in either the 2- or 3-position.…”